Printer having a thermal head

Abstract

In a serial thermal transfer printer or serial thermal printer comprising; a thermal head having a plurality of heat elements arrayed in a line; and means for selectively energizing and driving the plurality of heat elements in synchronous relation with the relative movement between the thermal head and the ink ribbon or heat sensitive paper, wherein when printing dots are successively positioned in the direction of the relative movement between the thermal head and the ink ribbon or heat sensitive paper, printing timing of the last dot is set ahead so as to be earlier than normal printing timing. When the previous printing data is "1" (recording) and the subsequent printing data is "0" (not recording), the position of the present printed dot is shifted toward the previous printed dot to compress the entire width in case of two or more successive dots. Since the printing head is traveling continuously during printing, the position of the present printed dot can be shifted toward the previous printed dot by advancing the printing timing. If the previous printing data is "0" and subsequent printing data is "1", it is apparent that a similar effect can be obtained by setting the printing timing backward so as to shift the position of the present printed dot toward the subsequent printed dot.

What is claimed is: 
     
       1. A printer having a thermal head comprising; a thermal head having a plurality of heat elements arrayed in a line; head driving means for bringing the heat elements into close contact with an ink ribbon or with heat sensitive paper; conveying means for moving said thermal head with respect to said ink ribbon or heat sensitive paper in the direction crossing the heat element line; and means for selectively energizing and driving said plurality of heat elemetns in synchronous relation with the relative movement between daid thermal head and said ink ribbon or heat sensitve paper, said means for selectively energizing and driving including means responsive to both previous printing data and subsequent printing data so that when printing dots are successively positioned in the direction of the relative movement between said thermal head and said ink ribbon or heat sensitive paper, printing timing of the last dot is set ahead so as to be earlier than normal printing timing. 
     
     
       2. A printer having a thermal head according to claim 1, wherein when printing dots are successively positioned, and the previous printing data is recording and the subsequent printing data is not recording, the position of a present printed dot is shifted toward the previous printed dot.   
     
     
       3. A printer having a thermal head comprising; a thermal head having a plurality of that elements arrayed in a line; head driving means for bringing the heat elements into close contact with an ink ribbon or with heat sensitive paper; conveying means for moving said thermal head with respect to said ink ribbon or heat sensitive paper in the direction crossing the heat element line; and means for selectively energizing and driving said plurality of heat elements in synchronous relation with the relative movement between said thermal head and said ink ribbon or heat sensitive paper, said means for selectively energizing and driving including means responsive to both previous printing data and subsequent printing data so that when printing dots are successively positioned in the direction of the relative movement between said thermal head and said ink ribbon or heat sensitive paper, printing timing of the first dot is set back later than normal printing timing. 
     
     
       4. A printer having a thermal head according to claim 3, wherein when printing dots are successively positioned, and the previous printing data is not recording and the subsequent printing data is recording, the position of a present printed dot is shifted toward the subsequent printed dot. 
     
     
       5. A printer having a thermal head comprising; a thermal head having a plurality of heat elements arrayed in a line; head driving means for bringing the heat elements into close contact with an ink ribbon or with heat sensitive paper; conveying means for moving said thermal head with respect to said ink ribbon or heat sensitive paper in the direction crossing the heat element line; and means for selectively energizing and driving said plurality of heat elements in synchronous relation with the relative movement between said thermal head and said ink ribbon or heat sensitive paper, said selective energizing and driving means including pulse generating means for generating pulses at a predetermined timing position for printing successive dots are successively positioned in the direction of relative movement between said thermal head and said heat ribbon or heat sensitive paper, said pulse generating means including means responsive to both previous printing data and subsequent printing data for enabling shifting the pulse timing position for the present printing data. 
     
     
       6. A printer having a thermal head according to claim 5, wherein said pulse generating means shifts the pulse timing position for the last dot to be printed of said successive printed dots ahead so as to be earlier than the predetermined timing position therefor. 
     
     
       7. A printer having a thermal head according to claim 5, wherein printing dots are successively positioned, and the previous printing data is recording and the subsequent printing data is not recording, said pulse generating means shifts the pulse timing position for a present printed dot toward the previous printed dot. 
     
     
       8. A printer having a thermal head according to claim 5, wherein said pulse generating means is responsive to both the previous printing data and the subsequent printing data for shifting the pulse timing position of the first dot of said successive printing dots to be later than the predetermined pulse timing position therefor. 
     
     
       9. A printer having a thermal head according to claim 5, wherein when printing dots are successively positioned, and the previous printing data is not recording and the subsequent printing data is recording, said pulse generating means shifts the pulse timing position of a present printed dot toward the subsequent printed dot.